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Varieze engine mount angles


PanamaRed

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  • 1 month later...

 I drove 600 miles one way to look at this project . Denver Craigslist .

the big red flag was that the motor mount stubs were all cockeyed drilled out weird  and the rest  of the workmanship look marginal.  Waste of time for me . He assured me it was excellent workmanship but he didnt know anything about it . 

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Edited by Ratdog
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I don't think the twist in the firewall mounts is a problem.  Here is a pic of another project that seems to have the same twist.  The mounts in your Craigslist plane have been beefed up (doubled up) so that's good.    If you plan to buy a mount from the Cozygirrls, you could call them for the dimensions.  The tubes on the mount ought to fit in the angles without a lot of shims.  I don't have any Varieze plans to check..  If you Google Images for Varieze firewall or Long-ez firewall, you'll see more pics of the firewall and mount and get the idea.  Most of the EZ pics I see have the mounts square and horizontal but it might not be the same in the Vari.

Found that pic here  https://afors.com/aircraftView/47034

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Edited by Kent Ashton

-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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10 hours ago, Ratdog said:

The one for sale  is just not right as i compare them . Big red flag . 

I could be wrong but I don't agree this is problem.  IMO the only thing that matters is that the angles stick straight out (i.e., aligned with the fuselage centerline) , they are parallel to each other, and the spacing is correct plus or minus a washer or two.  It that is the case, the engine mount should fit on the angles just fine.  The fact that the builder doubled them up shows he was aware of the cracking problem when the original single angles were used with bigger engines.  I wouldn't automatically condemn the mounts.

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-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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The thing that really concerned me was that they didnt seem to be at the same station vertically on the fuselage one was lower than the other . He claimed it was ok for the engine to be tilted a little .  It was too much for my lack of experience or knowledge . All i know is what it shows on the plans . 

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On 9/23/2021 at 7:16 AM, Kent Ashton said:

I could be wrong but I don't agree this is problem.  IMO the only thing that matters is that the angles stick straight out (i.e., aligned with the fuselage centerline) , they are parallel to each other, and the spacing is correct plus or minus a washer or two.  It that is the case, the engine mount should fit on the angles just fine.  The fact that the builder doubled them up shows he was aware of the cracking problem when the original single angles were used with bigger engines.  I wouldn't automatically condemn the mounts.

Could you educate me on the problems of the engine mount cracking issue .  What size engine is this a problem.  Here is a video on another project i want to buy .  The quality of workmanship on the engine mount studs is striking compared to the one in Denver.  I would like to put an 0290 on this but having trouble finding a conical mount for the varieze. 

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Could you educate me on the problems of the engine mount cracking issue .  What size engine is this a problem.  Here is a video on another project i want to buy .  The quality of workmanship on the engine mount studs is striking compared to the one in Denver.  I would like to put an 0290 on this but having trouble finding a conical mount for the varieze. 

The video didn't show for me.  I don't know if the engine mount angles on the Vari developed cracks but some of the EZs did.  Pic from Open-ez drawing A4 below.  The original angles were only 1/8" aluminum. 1/8" seems a little thin to me anyway.  Not sure why they crack; It could be from the way the holes were drilled and deburred and/or fatigue.  I probably saw it in the Canard Pushers (which, BTW, you should be reading if you want to own a Rutan airplane).  I've seen various ideas for beefing them up: doubling (as in your pic), switching them for steel angles or 1/4" extrusion, or making a stouter mount from a square steel tube. 

Screen Shot 2021-09-24 at 2.07.16 PM.png

-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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Couple of things from the Canard Pushers. 

Quote

[No. 27 -

Engine mount and mount extrusions - The older conical-type engine mount had tubes that were flexible enough to accommodate minor variances in the positioning of the aluminum angle extrusions in the fuselage. The new mount designed for the Lycoming dynafocal configuration has extra supports and is very rigid. Extreme care was taken to make the Brock welded mount accurate, to fit the extrusions, however normal tolerances may preclude a good fit on all airplanes. Thus, we are recommending the following method to assure an acceptable fit: Before allowing the extrusions to cure in place in the fuselage, clamp the welded mount to them. Shim with additional plies of BID if needed on the fuselage and centersection spar. Let the extrusions cure with the welded mount clamped in place.

Quote

No. 38 -

CAUTION - Long-EZ
Note that the engine section of the plans, Section IIL updates Section I of the plans. Do not do any work in the area of engine mount installation, brake master cylinder installation or anything aft of the firewall until you have Section IIL in hand. Also - do not install the aluminum engine mount extrusions until you have the engine mount at hand and can clamp it to the extrusions while they cure in place. This assures a perfect match of engine mount to extrusions.

Quote

No 80 -

When the Long-EZ was designed, the VariEze Lycoming 0-235 installation plans were used as the basis for the Long-EZ engine installation. There were no modifications to the steel weldment (mount) or to the interface to the fuselage (aluminum extrusions). The plans-built Long- EZ, including the prototype, N79RA, have exactly the same engine mount as the VariEze (which was originally designed for the Continental 0-200 which weighed only 190 lbs.)

Many builder/flyers have seen fit to install larger engines than authorized by the plans. These builders must realize that they have now taken on the responsibility of designing their own engine installation. RAF has not designed the Long-EZ engine mount to handle any engine larger than the Lycoming 0-235 or the Rolls Royce Continental 0-240.

Simply bolting a larger engine onto the 0-235 engine mount is asking for trouble. The extra weight and, more importantly, the extra vibrating mass of the engine/prop extension/prop may eventually result in cracks in the tubular engine mount.

By all accounts, the first indication is what feels, to the pilot, like a rough running engine. Should you notice a sudden, unexplained roughness or harshness from the engine compartment, land as soon as possible, remove the cowling and conduct a thorough examination of every tube and weld in the engine mount weldment using a strong light. If any cracks are found, do not fly again until this problem has been repaired.

What to do about this? Unfortunately, RAF is no longer in a position to be able to design and test a new engine mount so, it really is up to each builder/flyer. At the very least, a few well-designed gussets, strategically placed, or even a six point mount, may be required - are there any mechanical engineers out there willing to take on this task?

In the meantime, inspect your mount often and please report all incidents of cracking to RAF.

 

-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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Weird the plans i have ( from the cd ) show two different mounts for the varieze compared to the longeze .  I tested this on my friends varieze  .  The conical long-eze mount would not fit on the stubs of his varieze. The varieze mount ( dynafocal ) fit perfectly . The long eze mount was fabricated by cozy girls as per the plans .  The plans show different stub spacing for each aircraft according to what i have on the cd . Now im really confused now that it says above they Are the same . 

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1 hour ago, Ratdog said:

Weird the plans i have ( from the cd ) show two different mounts for the varieze compared to the longeze .  I tested this on my friends varieze  .  The conical long-eze mount would not fit on the stubs of his varieze. The varieze mount ( dynafocal ) fit perfectly . The long eze mount was fabricated by cozy girls as per the plans .  The plans show different stub spacing for each aircraft according to what i have on the cd . Now im really confused now that it says above they Are the same . 

Disregard this i need to do some more measuring 

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No i have access to a varieze project that just hapoens to come with a dynafocal mount for lycoming .  My problem is i have an 0290 comical so i  assumed  that the varieze and lomgeze used the same mount and purchased the cozy giirl conical longeze mount .  It doesnt fit the varieze project so i need to figue out why or obtain a mount that does fit or go to a 0235 engine and use the dynafocal mount that does fit . 

Edited by Ratdog
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9 hours ago, Ratdog said:

No i have access to a varieze project that just hapoens to come with a dynafocal mount for lycoming .  My problem is i have an 0290 comical so i  assumed  that the varieze and lomgeze used the same mount and purchased the cozy giirl conical longeze mount .  It doesnt fit the varieze project so i need to figue out why or obtain a mount that does fit or go to a 0235 engine and use the dynafocal mount that does fit . 

If you print out Open-EZ drawing A4 (firewall) from the Open-ez plans on this website, you could compare the EZ mount dimensions to the Varieze drawing you have.

 

-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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Yes im in the process of comparing them . It may be that i have a unique varieze. The dynafocal that came with it fits fine but the conical long eze mount is off in the vertical distance between the engine mounting studs .  Here are photos of the 2 mounts the brown one dynafocal fits fine .  The yellow one conical longeze is off on the upper studs .  You can see in the photo i marked where the brown dynafocal is .  If you line up the lower ones the upper ones are both off for the loneze mount as shown in the photo . 

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I’d say you’re looking at a 3rd mount.    😞.   I made one and it has several hundred hours on it by now.     You can buy the prewelded dynafocal ring.   ( I have one hanging in my basement I need to sell.).    Use .049 wall tubing, fit and tack it, take to a professional weldor to complete the welds.  Let the mount cool between welds.    Mine warped a tiny bit in one corner but I was able to muscle it into position.   Tig’d it myself and I am just a hack weldor

-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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3 hours ago, Kent Ashton said:

I’d say you’re looking at a 3rd mount.    😞.   I made one and it has several hundred hours on it by now.     You can buy the prewelded dynafocal ring.   ( I have one hanging in my basement I need to sell.).    Use .049 wall tubing, fit and tack it, take to a professional weldor to complete the welds.  Let the mount cool between welds.    Mine warped a tiny bit in one corner but I was able to muscle it into position.   Tig’d it myself and I am just a hack weldor

This. If you can operate a hacksaw, a tape measure and a bastard file your in business. There is a discussion in another canard group (I forget which one) where a guy fabricated an engine mount. The welding is the hardest part. He stabilized (bolted) his mount between two pieces of plywood to weld it.

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All it has to do is be at the circle drawn on the cardboard on borh sides at the top ( see photo) i dont  know why you couldn’t just weld an appendage to it its about an inch  off on both sides on the top 2 only . The bottom is fine 

image.jpg

Edited by Ratdog
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16 hours ago, Ratdog said:

 i dont  know why you couldn’t just weld an appendage to it its about an inch  off on both sides on the top 2 only . The bottom is fine

You could do that but it would be pretty ugly and still take welding.   The diagram above looks like a very simple mount to build: straight tubes, a couple of large washers, one tube with a bend you can probably buy or find a fabricator or hot-rod shop to bend for you.  This bend   https://www.markwilliams.com/12041.html   is plenty stout and will make four bends (you get two U’s).    In fact, I have one I will sell you for $20.  It's 9.5" long.  If it's too short, extend it with some more tube. 

https://www.kitplanes.com/home-shop-machinist-45/

Edited by Kent Ashton

-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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So i finally figured out whats going on with this varieze project .  The mount stub locations are off from the plans .  Therefore the dynafocal mount that fits is custom and not according to plans .  If i want a conical mount i will have to have it custom made to that configuration .  The other one i have ( conical ) will not fit unless i put another angle on it lower down which is not quite the longeze method . See photo below of my mockup . The inner circle drawn in the last photo is where the dynafocal ( custom mount ) hits the firewall .  An angle iron would have to be bolted to the existing one to make the yellow mount work . The last photo shows the posiition of the mount i want to work (red circle ) compared to the mount i have that fits( dynafocal ) 

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